Hydrogen peroxide was the vital ingredient in rock pores around underwater heat vents that set in train a sequence of chemical reactions that led to the first forms of life, according to lead researcher Rowena Ball from the Australian National University (ANU).
"The origin of life is one of the hardest problems in all of science, but it is also one of the most important," said Ball, from the ANU. Researchers made a model using hydrogen peroxide and porous rock that simulated the dynamic, messy environment that hosted the origin of life.
"Hydrogen peroxide played multiple roles in the emergence of living systems, and this study investigated how it ensured the randomly fluctuating temperatures and pH levels necessary to energise the production of a chemical world that made life on Earth possible," she said.
The study, published in the journal Royal Society Open Science provides new and valuable guidelines in the search for extraterrestrial life. "Our simulations reveal the importance of long rock pores or lengthy, interconnected porous structures in enabling the creation of long, large molecules," Ball added.
The research advances upon previous studies by modelling the flow of reactive species through porous rock rather than through a single pore. Ball said the high temperature fluctuations must not rise too high or occur too often.
"The system needs to spend enough time at higher temperatures to carry out essential synthetic reactions, but not so much that the reactants are totally consumed or destroyed. We call this the 'Goldilocks' distribution," she said.
"This effectively gives us the 'fundamental equation of life'. It says that for life to begin and persist, the habitat must exhibit a specific range of temperature fluctuations," she said. Hydrogen peroxide also promoted the evolution of enzymes called catalases that prevented a second 'origin of life' event.
"The ubiquitous presence of life, and hence catalases, in all habitable environments prevent hydrogen peroxide from accumulating sufficiently anywhere to drive a second origin event," Ball said.